The present invention relates generally to apparatus for handling of live fish, and particularly to handling of live fish in an automated marking operation such as severing fish fins.
The practice of marking hatchery fish supports efforts directed to protection of wild fish species. Marking hatchery fish provides a basis for distinguishing between wild fish and hatchery fish. Typically, marking is accomplished by severing a particular fin of the hatchery raised fish. Fisherman catching a fish without marking, i.e., with all fins intact, conclude the fish is a wild fish and return the fish to its natural habitat. The marked hatchery fish, however, are available for capture and use without restriction. Heretofore, only specific species of hatchery fish have been marked.
Mass marking across more species and for larger numbers of fish, however, is a growing trend in the fish management. Mass marking of hatchery fish has been proposed as a solution to a variety of difficulties encountered in the management of fish populations. There is growing political support for a mass marking program for hatchery fish in, for example, the Upper Columbia River Basin to more easily differentiate hatchery fish from wild fish. Thus, marking of all hatchery fish is important for protection of our declining wild fish populations. This is an evermore urgent goal and has been recognized as an important step in the preservation of wild fish species.
Prior marking techniques have been generally manual intensive techniques. In particular, each fish is individually handled and a selected fin severed with, for example, scissors. While the process has worked in the past, it will not work well for larger volumes of fish. Heretofore, fish management agencies have relied on volunteers to mark hatchery fish. Unfortunately, such volunteers can be hard to enlist and often are not always available long enough to complete a given batch of hatchery fish. Government agencies are then left with the difficult task of completing the marking procedures with insufficient staff after their volunteers have gone home.
Furthermore, the manual marking of fish tends to be not only slow and limited in productivity, but also provides opportunity for injury and infection to the fish. In particular, the extensive handling and prolonged time under anesthesia reflect badly on fish health, and in many cases result in fish death. Handling of fish increases the possibility of infection due to the loss of the fish's protective coating during manual handling. Mortality rates estimated as high as 40% result from traditional fish marking methods.
It would be desirable, therefore, to mark massive fish populations prior to their release into natural habitats without excess cost and with reduced risk of injury or death to the fish. Because fish populations are managed by government agencies, cost and efficiency are important to maximize government expenditures in implementation of wildlife protection policies.